Tecsun PL600vs550 comp test

(as noticed the radio has already been given )

Here is a special article on how PL600 differs from 550 !

Last week i took the 550 from my relatives house for a short timed exhaustive check on the similarities and the differences between them. Believe me this radio has many major and minor upgrades to 550 that seems a rather different product! Also notice that my PL are come from the earlierst bunches they made (ard 95 ?)

Look at both here! They seem as the same !

Just start from the external design for the differences :

POWER LOCK TIMER is for the 550

POWER TIME-SET TIMER 1 TIMER 2 for the 600

By this way the lock button gets rid from here (correct ! )and appears in another position ,later shown. They put the time set for easier time processing

Now on the display:

Here is the 550's LCd display:

And here is the 600's display

Nearly not so significant . ut there are 2 minor changes: The battery indicator on 550 is shown as graph in the S meter while the indicator on the 600 is shown inside the battery

Now on the board :

550 :

600

and now on the remain 550 :

the image is turned by 90 degress:

knobs: tuning knob , antenna tuner , volume

light snooze /tuning mode ------- page /scan mode/if shift /bw&stereo

and for the 600

tuning knob , BFO/ volume

light/snooze - tune fast slow & lock ------ preset- page- ssb- fm stereo& BW

And now more on the operation:

0 600 memories instead of 550 !

1. ON the 600 you may add two more bands (mostly useless ! ) LW and AIR .

I have tried several times to listen to the AIR band after using my Yupi scanner but still using strong signals on the YUpi , nothing could be found on same freqs on 600 except sometimes harmonics from shortwave stations. On LW the signals were very very poor !

2. Antenna switch : the switch is rather and attenuator with more than 20 db in the normal mode quite higher than the 550 . Tha means all signals it can be used only in very strong signals. I just have to keep it on the DX mode

3. The MW band sensitivity that seems quite poor on the 550 , is quite better on 600 though this is under discussion

4. The radio bands are here: full 150- 30000 mHz in LW (150-500) MW (500-2000) SW(2000-30000) 78-108 for FM (adjustable to 88-108) VHF 118-138 MHz with AIR and LW firmware activated and vv.

5. The BFO here replaces the 550's antenna tuner and operates together with the SSB button with a ca 3 kHz range. Did not test in full

6. The tuning knob has a very nice feeling Its tuning does not have any gaps as in the 550 and is very smooth. Using the tuning button you select between fine tuning (1 kHz AM , 10 kHz FM) fast tuning (MW 9 or 10 / SW 5 / FM 100 kHz /VHF 50 kHz ) and auto tuning (fast or slow depending on the speed )

7. Audio levels nearly same from ears and speaker . ON 550 audio was stronger on earphones

8. Audio Fidelity : 550 has better fidelity in all cases : Using speakers the 600 comes bassier in all cases . FM is very clear from speakers for both though 600 gives still bassier audio. Using earphones on FM, the quality goes over 550 with more trebles.

9. AM filter bandwidths : 550 has broader bandwidths. A very strong station can be listened 40 kHz far. narrower bandwidth increases sensitivity . IN contrast the 600 has narrower bandwidth and slightly decreases sensitivity.

10. Fm band images : 600 has lower image levels than the 550 and come from stringer signals only . For example 79.2 mHz comes from 100.6 . the 550 had stringer image or this station .

11. SW band images : Images on 600 are nearly nonexistent . A image signal of 550 on 4995 dd nt exist on 600

12. Found that the correct freq for 600 is tuning off by -1 kHz !

13. The 550 had no good AGC . Strong stations are heard quite louder than the poorer.

14. 550 upon start , while using ears does a strong sound that might destroy the ears. 600 solved this problem

About radios sensitivity!

this is still under discussion as it was for easier to test 600 with 1102 than 550 !!! Using my diversity 'theorem' again here:

Two radios are used close to other. Their telescopic antennas are unfolded in the same length / surface. Ear buds are connected into respective audio outs of radios one earbud is used for a head diversity audio. First audio is determined by a strong and clear station so that both single ear buds generate a mono sounded audio in your head (i.e. at the center ).This is what we can scale 5 at a scale of 1-9. For a very poor signal if an audio is stronger in the left side will will rated from 1-4 and on the right side at 6-9 with 1 and 9 being the only sounded points. UNder this theorem which audio is stronger , can mean a higher sensitivity towards the corresponding radio.

Using this theorem 600-550 were determined as 1-9 in this scale . I used the Sandisk Fuze and the Koss 315 ears

MW band: this was the most difficult as here this theory is invalid and required further scrutiny with diferrent reference audio stations (I used 1044 kHz a local station from ERA ) . BY a way both radios seemed to have the same sensitivity (though 600 signal indicator shown higher signals!) though as per the list below most signaling goes to 600 (with one reason 600 being bassier ):

530 2

576 3

648 4

801 4

900 2

1008 2

1133 6

1240 4

but extending it could lead to errors

SW band: here the problem is less difficult than the MW . I Used the 9420 kHz as reference freq to manage the diversity numbers . Using on start 1044 it lead me to some level of errors . A second point is that in all cases i fine tuned the ATU that lead to some higher noise levels while looking at nearly marginal signals

3965 6

3985 5-7

4930 7

4940 5

5950 5

5975 7

6025 6

6030 8

6310 9

6976 8

7320 6

7480 4-6

9526 7

9895 8

11535 5

12095 5

13660 5

15110 5

15330 3

15745 6-7

17550 7

17560 9

Again here there was the problem of the bassy 600 that made the feeling of some shift leftwards. As in result from the above , 550 seems having slightly (?) higher sensitivity levels to 600 and in some cases (bold numbers ) outperforms it.